The original in MD was waterfowlers were to use orange also. That got taken out with a quickness. In PA they were responding to an uptick in "mistaken for turkey" incidents. If you're in MD in a treestand you're not required to do it. Much as I hate to say it I can see how it might be a problem, had some rabbit hunters walk right up to me this year and not see me. They knew I was around because of my dekes and still let their dogs go right where I was.